1. Field of the Invention
The present invention relates to a packet flow control apparatus and a method for controlling the flow of packets on a network such as the Internet.
2. Description of the Related Art
Recently, in communication systems using variable length packets such as the Internet, provision of a so-called “quality-guarantee type service”, which assures the quality so as to avoid a delay at an end-to-end connection or a communication band to be always occupied, has been examined by IETF (Internet Engineering Task Force) and the like.
In the above-mentioned quality-guarantee type service, the information including a flow of sending packets, etc., is previously provided in accordance with a control unit formed of each packet flow, collection of packet flow, a destination of packet, etc., in the network of a user side or a sending side. Further, various resources provided within the network are previously reserved for the above user in a receiving side in accordance with the above information from the sending side.
In this case, however, if a packet, which does not comply with the above information, is sent from the user side or sending side, the resources provided within the network are unexpectedly congested (i.e., the resources becomes busy) so that the transferring quality from the sending side to the receiving side may be worse because of congestion of the network. Accordingly, when the congestion occurs in the network, it is necessary to control packet flow so as to be included in a range which was previously reserved in the user side or sending side network. In a conventional art, a token bucket algorithm is used as a sending control function of an IP (internet protocol) packet in IETF service, in order to realize the above control of the packet flow.